[Fan drive -- how much current?]

I've made a fanduct for two 40mm fans. Both are 0,05A 12V. Only at 80% fanspeed they turn very slowly, on lower or higher fanspeed nothing.

The fans run perfectly at 12V form a power supply. The original ones draw 0,09A, the new ones 0,05A.

Has anyone got a clue?

 

[Updated UM2 Fan Mount]

@pad interesting. Do you think the air is flowing too much around the heating element?

 

[Updated UM2 Fan Mount]

Just updated the model with 1mm more space around the heater, and also posted the dual head version.

A colleague of mine with a lot of process experience told me the heat is conducted through convection. A measure would me to put a heat shield in between, but it should not touch the plastic. So a thin sheet of alu foil would possibly work.

 

[Updated UM2 Fan Mount]

So far I've printed a few parts @250°C and some sagging occurred indeed, but the part didn't become disfunctional. In the next iteration the plastic will be a little further from the heating element.